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  1. Nonlinearer

    Continuity of precast beam's bottom rebars through precast column

    In precast beam-column moment connection where precast beam is resting on corbel of precast column and top rebars of beam are made continuous through precast columns in top cast-in-place part of precast composite beam, is it necessary to continue some of the bottom bars of precast beam through...
  2. Nonlinearer

    Provisions of Chapter 21 in Linear Elastic Range of Response

    Inelastic response is necessary. The approach of all seismic codes including ACI/ASCE requires to design for inelastic behavior. If we compare moderate wind and moderate EQ forces for a 5 story framed building, ELASTIC EQ forces will be approximately 8 to 10 times higher than wind. Thus making...
  3. Nonlinearer

    ACI318M-11, 10.6.7, Skin Reinforcement

    In my ACI318m-11 (metric version), clause 10.6.7, the requirement of skin reinforcement arises if beam depth is more than 400mm. Can any body check? What I remember, it was 900mm (36") in previous codes. If this is a typo, is it covered in errata? IR
  4. Nonlinearer

    Diaphragm action

    I am working on a housing scheme which consists of 2 story small buildings which are all repetitive. The scheme is to use precast planks(may be hollowcore or solid)resting on load bearing wall panels (External are sandwich panels). To speed up the work, client is suggesting to remove/minimize...
  5. Nonlinearer

    SAP 2000 modelling problem

    I have tried on your model. The only way when the Roof story shows the earthquake forces is to use Auto seismic load pattern under load pattern tab. Under Auto seismic, you can clearly define the height range. I have checked and it works. Probably, it requires more time to find out why the top...
  6. Nonlinearer

    SAP 2000 modelling problem

    Story means.....lateral load elevation range which should include your roof (max 'Z'. Also check your roof loading should be included in mass source for seismic load. IR
  7. Nonlinearer

    SAP 2000 modelling problem

    If you are using Auto seismic case, just check your story range under "Modify lateral load" tab; it should be roof. IR
  8. Nonlinearer

    Unexpected Moments at Beam End

    When giving releases, support moment should be zero. Just double check you are checking at support face. For detailed comments, you may upload your ETABS file. IR
  9. Nonlinearer

    Book/ literature on Non-Prescriptive Design of High-rise Buildings

    In general, I follow American Codes and Standards. Non-Prescriptive may be called Performance based design. Generally codes put height limitations, drift criterias etc. I am looking for any established standards/criteria/research for Tall buildings where we can move beyond code for more...
  10. Nonlinearer

    Control Displacement in a Restraints

    Use a spring initially and iterate the analysis until you get 20mm translation. IR
  11. Nonlinearer

    ACI 318-08 Section 7.12.2

    These are gross area ratios but one directional which is at right angle to the main reinforcement and may be distributed near top and/or bottom of slabs as appropriate. IR
  12. Nonlinearer

    Iterations/Reanalysis

    I think Iterations can not be directly defined for the analysis. However, under nonlinear, longterm, cracked & uplift cases Convergence tolerance can be defined which may limit the iterations for Nonlinear cases. But normally these tolerances shouldn't be changed much as these will affect the...
  13. Nonlinearer

    Where is min concrete grade for pre-cast (no prestress) walls specified?

    I don't see any Code specific minimum strength requirement. It all depends on the element which is to be precast. For example, in case of hollowcore slabs, it's always minimum 50Mpa, mostly 60 Mpa concrete as it is related to the method of casting where extruder machine is used and its almost no...
  14. Nonlinearer

    ASCE 7-05Chapter 15, Table 15.4-1 or 2?

    Table 15.4-2 refers to structures which are not similar to buildings & are mostly free standing like big vertical cantilevers. Whereas your case is similar to building, means you have vertical element (tower) and then the horizontal element which is your bridge thus more towards the building...
  15. Nonlinearer

    FEA gives an approximate solution? Why??

    When FEA is world wide an acceptable method of analysis then I don't think we can conclude something by discussing it why it is approximate. IR
  16. Nonlinearer

    Seismic R Value

    I don not know much about Tilt-up wall system but I think as the name implies, it is precast system of walls. Regarding ordinary & Intermediate walls, refer ACI-318-11, chapter 21. Generally, minimum strength of Intermediate precast wall is equivalent to Ordinary Cast-in-Place reinforced wall...
  17. Nonlinearer

    scale factor on ETABS

    Search in the Forum, I think this has been discussed before quite a few times. In general, this is a balancing factor of your Response spectrum base shear to the static base shear. For this, you should know your static base shear as per your Code of Practice. This can be calculated by selecting...
  18. Nonlinearer

    "Positive" moments

    I have seen your frame's BM diagram. This column is between the shear walls and shouldn't have this unusual behavior. I do not know your software but I can suggest to check the column properties and section input in to your software. It looks like a hanging column, check its connectivity with...
  19. Nonlinearer

    "Positive" moments

    What is the seismic Zone you are designing for? Also which software you are using? What is your lateral force resisting system? For (gravity + Seismic) load combinations, you might get reversal moments at supports. IR

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